Arsenic Removal from Groundwater by Electrocoagulation Process in a Filter-Press-Type FM01-LC Reactor

Treatment of groundwater containing arsenic by electrocoagulation (EC) has been studied in a filter-press-type FM01-LC reactor using 3 cell stack with aluminum as the sacrificial anode. The influence of current density and mean linear flow velocity on the As removal efficiency was analyzed. Groundwater was collected from deep well (320 m deep) located in Guanajuato, Mexico (arsenic 50 pg L-1, carbonates 40 mg L-1, hardness 80 mg L-1, pH 7.5 and conductivity 150 pS cm-1). Prior to EC experiments arsenite contained in groundwater was oxidized to arsenate by addition of 1 mg L-1 hypochlorite typically used for disinfection. Arsenate removal by EC might involve adsorption on aluminum hydroxides generated in the process. Arsenate depletion from 50 to 3.9 μg L-1 was obtained at current density and mean linear flow velocity of 6 mA cm-2 and 1.8 cm s-1, respectively, with energy consumption of 3.9 kWh m-3. The convenience of using the FM01-LC cell as a test reactor, which avoids oxygen evolution reaction during the aluminum electrodissolution, is also discussed.